Foldable escape ladders with adjustable rungs



K. c. MCLEOD 3,033,310

EOLDABLE EscAPE LADDERs WITH ADJUSTABLE RUNGs May 8, 1962 Filed Feb. 27,1961 Kenyon C. M QL eod ATTORNEY United. StateSIP-atent l3,033,310FOLDABLE ESCAPE LADDERS WIT ADJUSTABLE RUNGS v Kenyon C. McLeod, 167Madison Ave., Toronto,

l -Y Ontario,-Canada Filed Feb. 27, 1961, Ser. No..91,944 4 Claims. (Cl.182-196) This invention relates to an improved foldable ladder,especially usable as a fire escape, and which is extremely strong inconstruction, easily handled by the average person and which may bereadily stored.

A primary object of the invention is to provide a novel ladder of thecharacter mentioned and which includes novel means for the attachmentand adjustment of the ladder rungs.

Other objects and the nature and advantages of the instant inventionwill be apparent from the following description of an exemplaryembodiment taken in conjunction with the accompanying drawings wherein:

In the drawings:

FIG. l is a fragmentary perspective view of a ladder incorporating theinvention;

FIG. 2 is an enlarged side elevation of one of the novel rungs, lookingfrom left to right as indicated by line 2-2 of FIG. l;

FIG. 3 is a vertical section taken on line 3--3 of FIG. 2;

FIG. 4 is an enlarged fragmentary plan view taken substantially on line4-4 of FIG. 1;

FIG. 5 is a horizontal section taken substantially on the plane of line5-5 of FIG. 3;

FIG. 6 is an enlarged perspective view of a clamping element used in theinvention; and

FIG. 7 is an enlarged, exploded perspective view of one end of a ladderrung of the invention prior to insertion of an adapter block insertedtherein.

Referring to the drawing in detail a foldable or rope type ladder isindicated generally at 10 and includes exible side rails 12 of rope,cable, nylon cord, articulated links, etc., to which are adjustablysecured rung assemblies indicated generally at 14.

The rung assemblies 14 include tubular rung members 16 of any suitablematerial, steel, aluminum, plastics, etc., which in the exemplaryembodiment comprise a rectangular cross section to accordingly provide aflat foot-receiving surface 18 to which is secured or integrally formedtherewith a friction increasing surface such as a resilient pad 20,knurling, etc.

Mounted in the open opposite ends 22 of the rung members 16 areadjustable clamp assemblies indicated generally at 24 and whichcooperate with upper and lower, aligned transverse apertures 26 and 28formed adjacent the terminal ends of the rung members 16.

The clamp assemblies 24 include a mounting block 30 conforming to theopening 22 of the rung members 16 and received longitudinally therein.The block 30 is illustrated as having a rectangular cross section andhaving extending transversely through the upper and lower surfaces anenlarged rectangular bore 32 which is alignable with and of a greatercross sectional area than the aligned apertures 26, 28. The end wall 34of the block 30 includes a transverse, internally threaded bore 36 whichcommunicates with the bore 34 and adjustably retains therein a lock orclamp screw 38. The screw 38 will include a suitably formed head forreceiving a torque applying tool such as an Allen wrench, screw driver,etc., and in the instant case comprises a screw driver slot 40.

Received transversely through in diametrically opposed sides of theapertures 26, 28 are U-shaped clamp elements 42, 44 each of which beingidentical and interchangeable. The clamp elements 42, 44 each comprise3,033,310 Patented May' 8, f 1962 a vertical pressure-applying portion46 which is slightly concave-convex to conform to the outer surface ofthe flexible side rail with which it will engage. To aid in securing therung members in a iixed position, the pressure-applying portions includetransverse-.ribs on teeth 48. i; The ends of the portion 46 4terminatein upper and lower lips 50 and 52, respectively, which respectivelyoverlie the upper and lower surfaces of the rung member in which theyare mounted. It will be noted that the portion 446 of the clamp element44 is engaged by the clamp screw 38 as indicated at 54; see FIGS. 3 and5.

The rung assemblies are assembled as follows:

The block 30 is inserted into the open end 22 of the rung member 16 andthe screw 38 is backed off so it does not protrude through the aperture32. The clamp elements 42, 44 are inserted through the aligned apertures22, 34, 28 in opposed relationship. The ilexible side rail 12 is thenthreaded between the elements 42, 44 and the rung members 16 areadjusted to a predetermined position along the side rail. The screw 38is then rotated into engagement with the clamp element 44; see FIGS. 3and 5, and the teeth 48 aid to retain the adjusted position of the rungmembers. The screw 38 can be readily backed olf for subsequentre-adjustrnent.

Thus it will be observed that the novel flexible ladder is readilyassembled and includes parts which are readily constructed andmaintained. The rungs will be retained in their adjusted position. Theflat upper surface 18 and frictions surface give a user a feeling ofsecurity. The tubular rung members are especially strong and economicalin manufacture and the assemblies 24 are readily accessible from theopen ends 22 of the rung members.

The invention shown embodies the invention in a preferred form, however,it is intended that the disclosure be illustrative rather thandefinitive, and the scope of the invention is to be determined only asdefined by the appended claims.

What is claimed as new is as follows:

1. In a ladder, an elongated side-rail, and a rung assembly securedonsaid side-rail and projecting laterally therefrom, said rung assemblycomprising a rung member having an open ended, longitudinal bore andtransverse aperture means therethrough and through which said side-railextends, and side-rail clamp means accessible at the open end of saidlongitudinal bore of said rung member and projectionable intointersecting relationship with said transverse aperture means andadjustably and lockingly engaging a portion of said side-rail disposedin said transverse aperture means, a clamp block conforming to theinterior cross-section of the longitudinal bore of said rung member anddisposed in the open end of said rung member and including atransversebore in alignment with said transverse aperture means and through whichsaid side-rail extends, and a clamp screw mounted on said clamp blockand intersecting the transverse bore for engaging the side rail andmaintaining it fixed with respect to said clamp block, said rungassembly including opposed clamp elements disposed in said alignedaperture means and said bore at opposite sides of said side rail, saidclamp screw engaging one of said clamp elements and retaining the siderail between said clamp elements.

2. In a ladder as set forth in claim 1 wherein said side rail comprisesan elongated, ilexible, cord-like element, said clamp elements includingupper and lower lip portions overlying opposed upper and lower surfacesof said rung member, said clamp elements including opposed clampportions conforming to opposite side portions of said side rail.

3. In a ladder as set forth in claim 2 wherein said opposed clampportions include friction increasing portions, said side rail having across-section other than polygonal.

o 4. In a ladder as set forth in claim 3 wherein said rung member ishollow and has a rectangular crosssection providing means forstabilizing said clamp block, said rung member including a at uppersurface for providing a step upon which a users foot is readilyreceived. 5

References Cited in the file of this patent UNITED STATES PATENTS249,846 Macdonald Nov, 22, 1881 10 Rivers Nov. 25, 1890 Crosby Jan. 1,1895 Crosby Jan. 1, 1895 Buckley Sept. 21, 1897 Yoder Jan. 10, 1956FOREIGN PATENTS Sweden Feb. 18, 1947 Great Britain Aug. 22, 1929 GreatBritain July 16, 1958

